Automatic circuit controller for gaseous discharge devices



1942- J. A. MODERMOTT 2,305,096

AUTOMATIC CIRCUIT CONTROLLER FOR GASEOUS DISCHARGE DEVICES Filed June19, 1941 Fig"; 45 5 42 1 M M Julian Amuermow, INVENTOR.

ATTORNEY.

Patented Dec. 15, 1942 AUTOMATIC CIRCUIT CONTROLLER FOR GASEOUSDISCHARGE DEVICES Julian A. McDermott, Elmhurst, Long Island,

Application June 19, 1941, Serial No. 398,738

13 Claims.

The invention here disclosed relates to the control of circuits forgaseous discharge devices. The objects of the invention are to protectsuch circuits and apparatus forming parts of the circuit from the suddenvoltage rises which normally result from such causes as the removal of atube or the failure of a tube in the secondary circuit and to preventdamage or electric shocks of dangerous duration or intensity that mightresult from contact with or grounding of the high tension wiring systemand to continue such protection during all normal operating conditions.

In furtherance of such protection, it is an ob- Ject of the invention toeffect automatic opening of the primary circuit of the transformer uponthe occurrence of abnormal conditions in the secondary circuit and tomaintain the primary circuit open until the power supply is cut off andto repeatedly effect automatic opening of the primary circuit until suchtime as the abnormal condition in the secondary circuit is corrected.

The foregoing and other desirable objects are attained by novel featuresof construction, combinations and relations of parts all as hereinafterset forth, illustrated by way of example in the accompanying drawing andbroadly covered in the claims.

Figs. 1, 2, 3 and 4 are wiring diagrams illustrating four difierentembodiments of the invention.

Fig. 5 is a broken sectional detail of a special air gap constructionwhich may be used with and form part of the invention.

In the first embodiment of the invention illustrated, gaseous tubes 1and 8, are shown connected across the secondary winding 9, of atransformer suited to the purpose.

At some intermediate point H), of the secondary, a connection II, ismade to one side of a relay magnet [2, the other side of which isgrounded at IS.

The armature l4, normally cooperates with a contact IE, to close circuitthrough the primary winding l6, of the transformer.

One side of the primary circuit is shown as grounded at H, and some formof control switch is provided in the primary circuit, such asrepresented at l8.

In the event of abnormal conditions in the secondary circuit, such asmight result from removal or breaking of one or both of the tubes,causing an arc to ground at 22. or by a direct grounding of thesecondary circuit as by physical contact with some part of the secondarycircuit,

a surge of secondary current will extend from point 10 throughconnection H and relay I2, to ground at l3, causing the magnet to liftarmature ll, thus to interrupt the primary circuit at l5, and, byengagement with the upper contact l9, to put line voltage through thecoil, by way of armature I, connected with one side 20, of the line andcontact l9, through the coil to ground and, by way of the ground l1, tothe other side 2|, of the line. This provides the action of a doublethrow, self -holding relay, which first takes secondary current to openthe primary circuit and then holds the primary circuit open by linevoltage through an energizing circuit which it closes at l9, at the timeit opens the primary circuit at l5.

After the protective relay has operated as described to open and holdthe primary circuit open, the main switch l8, can be opened todeenergize relay l2, and permit the primary circuit to again close atI4, ii. If the grounded condition in the secondary has been corrected.then the main circuit can be closed at I0, and the armature M, willremain in engagement with contact ii. If however, the abnormal secondarycondition still exists and grounded current still can flow through therelay when primary switch 9 is closed, thenthe relay will repeat itsprotective function, continuing to act in this way until the fault inth. secondary has been cured.

It is intended that the minimum current required to actuate the relayshall be less than that of human resistance to shock, that is, less thanthe so-called let go" current.

To protect the equipment against abnormally high voltages, an arc gap orgaps 22, 22, of proper design and proportions may be connected in thehigh voltage circuit of the secondary. These are shown connected atopposite sides of the secondary winding and may be of diiferent valuesor dimensions to prevent a balanced condition.

As a substitute for or even in conjunction with the arc gaps 22, 22, areoperated contactors or so-called automatic cutouts 23, 24, whichautomatically close when an arc occurs across a gap,

may be connected either across the individual tubes 1 and 8, or, asindicated in the second instance, as at 24, in series with a spare tube25, for one of the tubes 8.

In Fig. 1, the failure of'tube 1, would then cause the contactor 23, tocomplete the circuit, due to the are that would result, and if the tube8 failed, the arc in contactor 2|, would cause the lighting of tube 25.

The high vcltage'protective feature of the arc gaps would be present inthe are operated cutouts 23, 24, but using these, the rate of operationof s48 relay should be slower than that of these cutouts, or the gapsmay be so dimensioned as to cause the parts to cooperatively function asdescribed. Commonly used means for retarding the action of relays may beemployed.

In general, the connection at II. for tripping the relay may be takenfrom any point or either end of the secondary winding.

If desired, an arc gap may be put in the relay circuit to ground, as inconnections Ii, running from the secondary tap it, to the relay coil.particularly where it might be desirable to have a direct groundconnection to the transformer secondary.

Fig. 2 illustrates a modification in which the holding circuit for therelay is accomplished without grounding the primary circuit.

In this case, the relay is provided with an additional winding 28,connected at 21, with the holding contact IS. The other side of thisseparate winding is connected at 28, with one side 2|, of the line.

The operation is similar to that first described. Abnormal conditions inthe secondary will occasion a flow of current through the relay magnetl2, which, as it picks up its armature H, interrupts at 15, the primarycircuit to the transformer and closes circuit at I9, 21, from one. side20, of the line through the holding winding 28, and connection 28, toother side 2|, of the line. The relay will then hold the primary circuitopen until conditions have been restored to normal in the secondarycircuit, such protection being afforded in this instance, withoutdepending upon a grounding of the primary circuit.

Fig. 3 illustrates a modification or a simplification of the invention,in which an abnormal voltage in the secondary produces an are at 29, or30, through a common connection 3 I, to the relay magnet l2, and groundat IS.

The armature of the magnet is sustained in this instance, by a springpressed trigger 32, pivoted at 33, and which can be tripped by pushbutton 34, to restore the primary circuit at l5, after conditions havebeen corrected in the secondary. In this particular form of theinvention, the secondary tap may be ground as indicated at 35.

Under certain conditions, it may be desirable to connect the relaybetween high tension points of the transformer circuit through a. gap orgaps.

Such an arrangement is shown in Fig. 4, where the relay winding is shownconnected through arc gaps 36, 31, across the ends of the transformersecondary.

In this particular illustration, upon energization of the relay, thearmature I4, releases a, spring tensioned contactor 38, to interrupt theprimary circuit at 39, which then remains open until abnormal conditionsin the secondary have been corrected and the contactor is returned. asby operation of a restoring button 40.

Thermal relays employing windings and bimetallic contact strips may besubstituted for the magnetic elements indicated. The action of suchrelays however, might be slower as so constructed and the protectivevalue thus lessened. The contacts employed may be of the mercurycapillary type, if current conditions warrant.

By connecting the primaries in multiple and by interconnecting thetransformer grounding connections, it is possible to use one relay ofthe types described to protect a number of transformer systems.

To make the relays operate properly and reduce sparking, condensers andor resistors that will 2 nswer under the special circumstances, may beemployed. Time controlled relays of the numerous types available may beused.

Various size arc gaps may be required, depending upon transformervoltages.

One form of are gap particularly suited to the invention is illustratedin Fig. 5. This comprises a metallic shell 4|, which may be ventilatedas indicated at 42, and which has insulated high tension terminals 43,II, at opposite ends of the same. Insulating bushings II, II, inopposite ends of the sleeve support the terminals and also carry, ininsulating cement 40, N, the electrodes 41, 41, dimensioned and spacedfrom the metal shell to determine the discharge voltages. The shell maybe supported in a suitable mounting and grounding clamp. The structureshown provides double arc gaps. but if only one are gap were desired,only a single spaced insulated electrode would be provided within theshell.

The invention provides an effective control and protection for gaseousdischarge devices, applicable at low cost to new or to existing systemsand providing full protection to apparatus and to those installing orservicing such systems.

What is claimed is:

1. In control apparatus, the combination of a transformer for gaseousdischarge tubes, a relay connected between a point on the transformersecondary and ground, contact means actuated by said relay to open theprimary circuit of the transformer and means for effecting the holdingof said contact means in said open primary circuit position untilabnormal conditions in the secondary circuit which occasioned energizingof the relay have been corrected.

2. In control apparatus, the combination of a transformer for gaseousdischarge tubes, a relay connected between a point on the transformersecondary and ground, contact means actuated by said relay to open theprimary circuit of the transformer, means for effecting the holding ofsaid contact means in said open primary circuit position until abnormalconditions in the Secondary circuit which occasioned energizing of therelay have been corrected, said last means including holding connectionsfor the relay .established in the primary circuit of the transformerwhen said relay is first energized.

3. In control apparatus, the combination of a transformer for gaseousdischarge tubes, a relay connected between a point on the transformersecondary and ground, contact means actuated by said relay to open theprimary circuit of the transformer, means for efi'ecting the holding ofsaid contact means in said open primary circuit position until abnormalconditions in the secondary circuit which occasioned energizing of therelay have been corrected, said last means including an additionalholding winding in the relay and connections for establishing currentflow through said holding winding when said relay is first energized.

4. In control apparatus, the combination of a transformer for gaseousdischarge tubes, a relay connected between a point on the transformersecondary and ground, contact means actuated by said relay to open theprimary circuit of the transformer, means for effecting the holding ofsaid contact means in said open primary circuit position until abnormalconditions in the secondary circuit (which occasioned energizing of therelay have been corrected, said last means including a manuallyreleasable trigger for mechanically retaining the contact means.

5. In control apparatus, the combination of a transformer for gaseousdischarge tubes, a relay connected between a point on the transformersecondary and ground, contact means actuated by said relay to open theprimary circuit of the transformer, means for effecting the holding ofsaid contact means in said open primary circuit position until abnormalconditions in the secondary circuit which occasioned energizing of therelay have been corrected, said last means including a trip operated bythe relay, said con-.

tact means being of the self-opening type and normally held closed bysaid trip and means for manually restoring said contact means and tripto the circuit closed condition 6. In control apparatus, the combinationof a transformer for'gaseous discharge tubes, a relay connected betweena point on the tr nsformer secondary and ground, contact mean actuatedby said relay to open the primary cir uit of the transformer, means foreffecting the holding of said contact means in said open primary circuitposition until abnormal conditions in the secondary circuit whichoccasioned energizing of the relay have been corrected and arc gapcontrol means associated with said secondary circuit.

'1. In control apparatus, the combination of a transformer for gaseousdischarge tubes, a relay connected between a point on the transformersecondary and ground, contact means actuated by said relay to open theprimary circuit of the transformer, means for effecting the holding ofsaid contact means in said open primary circuit position until abnormalconditions in the secondary circuit which occasioned energizing of therelay have been corrected, the secondary of the transformer beingconnected to groundv through an arc gap.

8. In combination, a transformer for gaseous discharge devices and arelay connected to be energized from the secondary of the transformerthrough an arc gap to ground from over-voltage v in the transformersecondary and connected to open the transformer primary when soenergized. 9. A controller for gaseous discharge devices,

comprising in combination with a transformer ated by said relay. 5

10. In a controller for gaseous discharge devices a transformer havingsubstantially constant/current characteristics, a relay connectedbetween the secondary winding of the transformer and ground, said relayhaving a winding for carrying the transformer secondary current and :areluctance sufficient to permit operation of the relay from line voltageand contact means controlled by said relay to interrupt the primarycircuit of the transformer and to connect said relay winding to linevoltage.

11. In control apparatus, the combination of a transformer for gaseousdischarge tubes, a

relay connected between a point on the transformer secondary and ground,contact means actuated by said relay to open the primary circuit of thetransformer, means for effecting the holding of said contact means insaid open primary circuit position until abnormal conditions in thesecondary circuit [which occasioned energizing of the relay have beencorrected, the secondary of the transformer being connected to ground ata point removed from the point of connection of the secondary with therelay through an arc gap.

12. In combination with a transformer for gaseous dischargetubes, thesecondary of said transformer being connected to ground through an arcgap, a relay operable by secondary circuit current and connected betweena point on said transformer secondary and ground, contact means operableby said relay to effect opening of the primary circuit of thetransformer, means for effecting the retention of said contact means insaid open primary circuit condition and a manually operable controlswitch in series relation with said contact means.

13. In combination .with a transformer for gaseous discharge tubes, thesecondary of said transformer being connected to ground through an arcgap, a relay operable by secondary circuit current and connected betweena point on said transformer secondary and ground, contact means operableby said relay to effect opening of the primary circuit of thetransformer, means for effecting the retention of said contact means insaid open primary circuit condition, a manually operable control switchin series relation with said contact means, said retention meansincluding holding connections in the primary circuit adapted to becompleted by operation of said relay.

JULIAN A. MCDERMO'I'I.

